Medical liquid administration set with optical liquid level indicator

ABSTRACT

A medical liquid administration set with an enlarged transparent measuring chamber that has two vertical opaque stripes on a rear half of the chamber and has volumetric calibrations on its front half. The transparent chamber wall, opaque stripes, and a transparent liquid partially filling the chamber combine to create an optical illusion of a lateral offset in at least one of the stripes between air and liquid in the chamber. This provides an easy-to-read indicator of liquid level within the chamber.

United States Patent 1 1 McPhee Nov. 27, 1973 1 MEDICAL LIQUIDADMINISTRATION SET WITII OPTICAL LIQUID LEVEL INDICATOR [75] Inventor:Charles J. McPhee, Sylmar, Calif.

[73] Assignee: American Hospital Supply Corporation, Evanston, Ill.

[22] Filed: Nov. 26, 1971 [21] Appl. No.: 202,243

[52] US. Cl. 128/214 C, 73/327, 222/158 [51] Int. Cl A61m 05/16 [58]Field of Search 128/213, 214 R, 214 E,

128/214 C, 214.2, 227, 272; 73/327; 84/97; 137/559; 40/310; 222ll57-159[56] References Cited UNlTED STATES PATENTS 3,690,312 9/1972 Leibinsohn128/214 R X 2,303,154 11 1942 Armstrong ..73 327 2,356,267 8/1944Pelunis 73/327 UX 3,216,419 11/1965 Scislowicz 128/214 C 3,217,70911/1965 Schneider et a]. 128/214 C FOREIGN PATENTS OR APPLICATIONS595,775 7/1925 France 73/327 Primary Examiner--Dalton L. TruluckAtt0rneyLarry N. Barger et a1.

[57] ABSTRACT A medical liquid administration set with an enlargedtransparent measuring chamber that has two vertical opaque stripes on arear half of the chamber and has volumetric calibrations on its fronthalf. The transparent chamber wall, opaque stripes, and a transparentliquid partially filling the chamber combine to create an opticalillusion of a lateral offset in at least one of the stripes between airand liquid in the chamber. This provides an easy-to-read indicator ofliquid level within the chamber.

6 Claims, 7 Drawing Figures Patented Nov. 27, 1973 2 Sheets-Sheet lPatented Nov. 27, 1973 2 Sheets-Sheet MEDICAL LIQUID ADMINISTRATION SETWITH OPTICAL LIQUID LEVEL INDICATOR BACKGROUND Administration sets areoften used to receive liquid from a suspended parenteral liquidcontainer and deliver it to a patient. Some of these adminstration setshave enlarged measuring chambers of less volume than the bottle. Thepurpose of these measuring chambers is to get a more accuratemeasurement of smaller volumes of dispensed liquid. For instance, anadministration set connected to a 1 liter (1,000 ml.) bottle might havea 100 ml. measuring chamber that is calibrated to within an accuracy of1 ml. The reason for this arrangement is that a large 1 liter bottlesdoes not have the volumetric accuracy of a small measuring chamber.

One of the main problems with these measuring chambers andadministration sets is that the liquid level is very difficult for anurse or physician to read. This is because the liquid and the wall ofthe chamber are both transparent. When a nurse or physician view thepartially filled measuring chamber from a distance it often appearsentirely transparent and a mistake could be made concerning how muchliquid is present in the chamber.

The problem is not nearly as pronounced when the liquid being dispensedhas a substantial color or tint to it. However, for medical reasons manyliquids being administered to patients are transparent. No foreigncoloring material is added, because a patient might react to suchcoloring material.

SUMMARY OF THE INVENTION I have overcome this problem of readilydiscerning the air-liquid interface within a measuring chamber of aparenteral liquid administration set where the liquid being administeredis transparent.

The transparent measuring chamber of my invention includes on its outersurface two vertical opaque vertical stripes that extend from top tobottom of the chamber. These stripes are on a rear half of thetransparent chamber while the front half has volumetric calibrations.The measuring chamber has a cylindrical transparent wall and whenpartially filled with transparent liquid combines with the two verticalopaque stripes to create an optical illusion of a lateral offset in atleast one of the stripes exactly at the air-liquid interface. The twostripes separated by vertical transparent section of the chamber createthis lateral offset illusion over a wide angle viewing range even thoughthe offset may appear different from different viewing angles. At someviewing angles the offset of one or more stripes appears to be on theleft, while at other view angles it appears to be on the right. At stillanother viewing angle the opaque stripes below the air-liquid interfaceappear to disappear altogether. From another viewing angle the twoopaque stripes below the air-liquid interface form an optical illusionthat blends them together so the entire chamber below the interfaceappears to be opaque.

THE DRAWINGS FIG. 1 is a front elevational view of the measuring chambershowing the optical illusion of the lateral offset in the two stripeswhen viewed straight on from its frontal calibrations;

FIG. 2 is a cross sectional view taken along line 22 of FIG. 1;

FIG. 3 is a view of the measuring chamber of this invention when viewedfrom the right of the calibrations;

FIG. 4 is a sectional view taken along line 44 of FIG. 3 showing thedirectional view;

FIG. 5 is a view of the measuring chamber taken from the left of thecalibrations along the direction shown in FIG. 6;

FIG. 6 is a sectional view taken along line 66 of FIG. 5 showing theviewing angle; and

FIG. 7 is a reduced front elevational view of the empty measuringchamber containing the two opaqure stripes and showing theadministration set connecting between a liquid supply bottle and avenous needle.

DETAILED DESCRIPTION The administration set described in this inventionincludes a flexible conduit 1. This conduit connects between a liquidsupply bottle and a patient as will be explained in more detail in FIG.7. Referring now to FIG. 1 the flexible conduit has an enlargedmeasuring chamber 2 connected in series with this flexible conduit. Thisenlarged chamber has calibrated inidicia 3 shown here to measure between0 and ml. If desired, the chamber can be made longer and have a capacityof ml. This chamber 2 includes a cylindrical transparent side wall 4connected at its upper end to a top cap 5 and at its lower end to abottom cap 6. The top cap has an inlet 7, an additive medicationpuncture site 8 and a valved vent system 9. The details of the top capand valve 9 are explained in more detail in a co-pending applicationentitled MEDICAL LIQUID ADMINIS- TRATION SET FOR RATE OR VOLUME DELIV-ERY, Ser. No. 202,505, filed Nov. 26, 1971.

Connected to bottom cap 6 is also a secondary drip chamber 10 with adrip former 11. The purpose of this secondary drip chamber is to measurethe flow rate of liquid in the administration set simultaneously withthe volume measurement taken in the enlarged chamber 2.

As shown in FIG. 1 the transparent chamber has an air-liquid interface12 which shows the chamber contains 90 ml. of liquid. As liquid isdispensed from this .chamber this interface or liquid surface level willdescend. Because the volume delivered is directly measured by interface12, it is very important to accurately know it s position.

In my invention there are provided two vertical opaque stripes l3 and 14which make interface 12 much more visible. These stripes 13 and 14 areprinted on an exterior its the transparent side wall. I have found thatopaque stripes of medium blue color contrast very well with thetransparent liquid in the chamber and the transparent chamber wallitself. As shown in FIG. 2 each stripe occupies approximately 50 of thecircumference of the cylindrical side wall. These stripes could eachcover between 30 and 65 of the cylindrical walls surface. Also eachstripe is spaced approximately 12 rearwardly of a diametric plane 15shown in dotted line in FIG. 2, but could be from 5 to 20 back from thediametric plane. There is a transparent segment between the two stripesof from 40 to 70 of the circumference of the chamber. This plane 15separates the rear half of the chamber from the front half. The fronthalf contains the indicia 3.

As shown in FIG. 2 the arrow 16 indicates the position of the viewer andthe direction of his eyesight. When the viewer looks head on intoindicia 3 the two opaque stripes l3 and 14 will appear as shown in FIG.

1. In FIG. 1 the two stripes are readily visible above interface 12.Below interface 12 the liquid which might be distilled water, normalsaline, etc., causes an optical defraction of the light rays causing thetwo stripes to optically disappear below the interface 12. Thisdisappearance is an optical illusion which provides very sharp apparentoffsets 17 and 18 at the interface 12. Thus a nurse can readily see howfull the chamber 2 is even though she may be several feet from theadministration set.

In FIG. 3 a very similar administration set is shown having conduit 20and enlarged chamber 21 with a top cap 22 and a bottom cap 23. Thechamber portion of this administration set is identical with that shownin FIG. 1 in regard to the indicia 24 and the opaque stripes 25 and 26.There is a slight modification in that the secondary drip chamber hasbeen eliminated and conduit connects directly to bottom cap 23. There isalso a float valve 27 maintained within a cage 28. As valve 27 descendswhen the chamber 21 empties it will shut off by seating against valveseat 29. Liquid flow into chamber 21 is controlled by roller clamp 30and liquid flow out of chamber 21 is controlled by roller clamp 31.

The sectional view through 44 as shown in FIG. 4 illustrates the opticalillusion created when the chamber 21 is rotated from that shown in FIG.2 so the viewer sites along arrow 32. The front and rear half of thechamber are still shown separated by a diametric plane 33. When theviewer looks at the chamber from this viewing angle the two opaquestripes and 26 give an optical illusion that the entire chamber beneathan interface 34 is opaque. In the drawings some of the numerals havebeen blanked out to better illustrate the opaqueness that appears belowinterface 34 when viewed from this angle. However, the actual chamber 21will readily show both the indicia 24 and the opaque stripes 25 and 26.This is because the indicia will be on the forward half of the chambertoward the viewer. The opaque stripes 25 and 26 will form an opaquebackground on a rear half of the chamber. The transparent liquid will bebetween the indicia and opaque background.

In FIG. 5 a chamber 40 is shown which is similar to the other twopreviously mentioned transparent chambers. However, here the two opaquestripes 41 and 42 extend only along the calibrated length of thetransparent side wall 43. The stripes 41 and 42 and indicia 44 all havethe same relationship to each other as the stripes and indicia of theFIG. 1 and FIG. 3 versions. As shown in the FIG. 6 sectional view, thechamber has been rotated so the viewer sites along arrow 46. The frontand rear half of the chamber are separated by diametric plane 47. InFIG. 6 the stripe 42 is not directly centered behind the viewing site ofarrow 46 and the optical illusion appears as shown in FIG. 5. Here, theinterface 48 is shown as having dropped to approximately 55 ml. becauseof liquid drainage. The opaque stripe 41 appears as a straight thin bandalong the left side of the chamber. Opaque stripe 42 appears tosubstantially widen at interface 48 to provide an opaque lateral offsetat both sides of stripe 42. Because of the viewing angle the two opaquestripes do not make the entire liquid portion of the chamber contents toappear backed by solid opaque background. At this viewing angle there isa transparent section 49. As in FIG. 3 the numerical scale has beensectioned out for purposes of clarity in the drawings. In' actual usethese numbers would be readily apparent to the viewer.

In FIG. 7 the chamber shown in FIG. 1 is illustrated in reduced scaleand attached to a liquid supply bottle 50 through a spike 51 at its topend and has an adapter 52 and venous needle 53 connected at its lowerend.

Also in FIG. 7 the chamber 4 is illustrated containing I no liquid.Since there is no transparent liquid to defract the light and create theoptical illusion, the two opaque stripes 13 and 14 appear as thinvertical bands along the left and right side of the chamber.

In the above description three slightly different measuring chambershave been used to illustrate my invention. However, it should be kept inmind that each of these three measuring chambers (FIG. 1, FIG. 3 andFIG. 5) have the indicia and two opaque stripes in the same annularposition relative to each other. The different appearing lateral offsetsin the opaque stripes occur because of the different viewing angles asrepresented by arrow 16 of FIG. 2, arrow 32 of FIG. 4, and arrow 46 ofFIG. 6.

In the foregoing illustrations and descriptions I have used specificexamples to describe my invention. However, it is understood that thoseskilled in the art can make certain modifications to these exampleswithout departing from the spirit and scopeof the invention.

I claim:

1. A medical liquid administration set comprising an enlarged liquidholding measuring chamber having a tubular transparent wall connected totop and bottom closures; said adminstration set having an inlet openingthrough the top closures; and an outlet opening through the bottomclosure, both of said openings being substantially smaller in crosssection than the transparent tubular wall; an inlet conduit and anoutlet conduit respectively connected to the inlet and outlet openingsof the closures, said inlet and outlet conduits being substantiallysmaller in cross section than the transparent tubular wall; connectormeans at an end of the inlet conduit for connecting with a liquid supplysource; adapter means at an end of the outlet conduit for dispensingliquid; said chamber including a front half and rear half; a pluralityof permanent, opaque stripes extending longitudinally on the rear halfof the chamber; said tubular transparent wall having an intermediatelongitudinal transparent area separating the opaque stripes; permanent,volumetric measuring indicia on a front half of the tubular transparentwall; the opaque stripes and volumetric measuring indicia having a fixedrelationship to each other regardless of rotational movement of atubular transparent wall relative to supporting structure; said opaquestripes and the longitudinal transparent wall section therebetweencombining and forming an optical illusion of a substantial lateraloffset at one or more of the opaque stripes at an interface between airand liquid when the measuring chamber is partially filled with liquidand the front half of the tubular transparent chamber is viewed fromwidely different viewing angles at the front of the transparent wallincluding the liquid level can be read at a substantial distance anderrors in reading are substantially eliminated.

2. The combination as set forth in claim 1 wherein the stripes areparallel to each other and to an axis of the cylindrical tubularchamber.

3. The combination as set forth in claim 2 wherein each opaque stripeshas a width of from 30 to 65 of the tubular chambers circumference.

4. The combination as set forth in claim 2 wherein each opaque stripe isspaced rearwardly from 5 to back from the diametric plane.

5. The combination as set forth in claim 1 wherein the opaque stripesare of a blue color to provide a clear optical contrast with thetransparent chamber wall and transparent liquid therein.

6. A medical liquid administration set comprising an elongated tubularconduit having an upper end portion adapted to connect to a liquidsupply source, a lower end portion adapted to connect with a patient; anenlarged volumetrically measuring chamber connected in series with theconduit, said chamber including a top cap, a bottom cap and acylindrical transparent wall having ends joined to said respective caps;two vertical parallel opaque stripes on said transparent tubular wall,said stripes being spaced apart by a vertical transparent section of thetubular wall covering between 40 and of its circumfemece, each of saidstripes occupying between 40 and 60 portions of the circumferentialdistance of the transparent cylindrcal chamber; both of said stripesbeing located on a rear half portion of the culindrical chamber definedby a vertical diametric plane; and volumetric indicia located on a fronthalf of the cylindrical chamber, the opaque stripes and verticallongitudinal transparent wall section therebetween combining to formoptical illusionary lateral offsets immediately adjacent one or more ofthe opaque stripes at an interface between air and liquid in saidmeasuring chamber partially filled with said liquid and the front halfof the tubular measuring chamber is viewed through widely differentviewing angles.

1. A medical liquid administration set comprising an enlarged liquidholding measuring chamber having a tubular transparent wall connected totop and bottom closures; said adminstration set having an inlet openingthrough the top closures; and an outlet opening through the bottomclosure, both of said openings being substantially smaller in crosssection than the transparent tubular wall; an inlet conduit and anoutlet conduit respectively connected to the inlet and outlet openingsof the closures, said inlet and outlet conduits being substantiallysmaller in cross section than the transparent tubular wall; connectormeans at an end of the inlet conduit for connecting with a liquid supplysource; adapter means at an end of the outlet conduit for dispensingliquid; said chamber including a front half and rear half; a pluralityof permanent, opaque stripes extending longitudinally on the rear halfof the chamber; said tubular transparent wall having an intermediatelongitudinal transparent area separating the opaque stripes; permanent,volumetric measuring indicia on a front half of the tubular transparentwall; the opaque stripes and volumetric measuring indicia having a fixedrelationship to each other regardless of rotational movement of atubular transparent wall relative to supporting structure; said opaquestripes and the longitudinal transparent wall section therebetweencombining and forming an optical illusion of a substantial lateraloffset at one or more of the opaque stripes at an interface between airand liquid when the measuring chamber is partially filled with liquidand the front half of the tubular transparent chamber is viewed fromwidely different viewing angles at the front of the transparent wallincluding the liquid level can be read at a substantial distance anderrors in reading are substantially eliminated.
 2. The combination asset forth in claim 1 wherein the stripes are parallel to each other andto an axis of the cylindrical tubular chamber.
 3. The combination as setforth in claim 2 wherein each opaque stripes has a width of from 30* to65* of the tubular chamber''s circumference.
 4. The combination as setforth in claim 2 wherein each opaque stripe is spaced rearwardly from 5*to 20* back from the diametric plane.
 5. The combination as set forth inclaim 1 wherein the opaque stripes are of a blue color to provide aclear optical contrast with the transparent chamber wall and transparentliquid therein.
 6. A medical liquid administration set comprising anelongated tubular conduit having an upper end portion adapted to connectto a liquid supply source, a lower end portion adapted to connect with apatient; an enlarged volumetrically measuring chamber connected inseries with the conduit, said chamber including a top cap, a bottom capand a cylindrical transparent wall having ends joined to said respectivecaps; two vertical parallel opaque stripes on said transparent tubularwall, said stripes being spaced apart by a vertical transparent sectionof the tubular wall covering between 40* and 70* of its circumfernece,each of said stripes occupying between 40* and 60* portions of thecircumferential distance of the transparent cylindrcal chamber; both ofsaid stripes being located on a rear half portion of the culindricalchamber defined by a vertical diametric plane; and volumetric indicialocated on a front half of the cylindrical chamber, the opaque stripesand vertical longitudinal transparent wall section therebetweencombining to form optical illusionary lateral offsets immediatelyadjacent one or more of the opaque stripes at an interface between airand liquid in said measuring chamber partially filled with said liquidand the front half of the tubular measuring chamber is viewed throughwidely different viewing angles.